The present invention relates generally to aquarium water flow control devices, and more specifically to an aquarium water flow control device which includes means for supplying a gas, such as air, to an outlet of the device when aquarium water covers and flows through the outlet.
In order to keep the water in a typical aquarium free from dirt, bacteria, algae, etc., it is necessary to either constantly change the water in the aquarium or to at least continuously filter the water. This is because life forms such as fish and plants which inhabit an aquarium excrete pollutants which can not only cause the aquarium to have an undesirable appearance, but can threaten the lives of the inhabitants. For example, if fish are kept in the aquarium, it is necessary to either constantly change the aquarium water or continuously filter the existing aquarium water so that the fish will not die in feces-ridden water. Constantly changing the aquarium water is normally extremely inconvenient and undesirable because of the following: aquariums are often large; inhabitants of the aquarium must be separated from the aquarium water before the water is to be disposed; and, inhabitants of an aquarium always live longer when not forced to re-acclimate to different aquarium water on a constant basis. As a result, aquarium water is usually continuously filtered rather than constantly changed.
In the case of larger aquariums, and in the case of salt-water aquariums in general, typically a filter is located below the aquarium in a cabinet and a pre-filter hangs on a wall of the aquarium. The aquarium water continuously flows from the aquarium, into the pre-filter, down to the filter, and back up into the aquarium. In this manner, the aquarium water is continuously filtered, and therefore kept free of dirt, bacteria, algae, feces, etc. Consequently, the aquarium has a desirable appearance and the life spans of the inhabitants of the aquarium are maximized.
The typical pre-filter will now be described. Normally, a pre-filter includes a means to keep fish from flowing from the aquarium and into the pre-filter. For example, the pre-filter may include a small box located inside the aquarium. The small box generally has an open top, and the small box is usually connected to a larger box that hangs outside the aquarium, on a wall of the aquarium. The top of the small box is located just at the surface of the aquarium water, and therefore, the aquarium water barely flows over the top of the small box and therein. To prevent fish from flowing with the aquarium water into this small box, the top of this box normally has, for example, upwardly extending flanges (or "teeth") with spaces therebetween. Consequently, while the aquarium water can flow between the spaces into this box, the fish cannot flow along with the water into the box because the spaces between the teeth are too small. Unfortunately, these teeth not only keep fish from flowing into the box, but also somewhat diminish the flow of aquarium water therein.
A siphon tube typically carries the water from the small box, over the aquarium wall, and into the larger box hanging outside the aquarium. The larger box includes an outlet and connected to the outlet is the first end of a hose. The other end of the hose is connected to the filter which is located below the aquarium in a cabinet. After the aquarium water flows into the larger box from the small box, the aquarium water thereafter flows through the outlet of the larger box, along the hose, and to the filter. After the water runs through the filter, the water flows along a second hose, and back into the aquarium. In this manner, the aquarium water is continuously brought from the aquarium, filtered, and carried back into the aquarium.
However, the rate of flow of aquarium water from the aquarium into the larger box is normally not equal to the rate of flow of aquarium water through the outlet of the larger box. As a result, the water level above the outlet and inside the larger box constantly fluctuates. Actually, the water level above the outlet typically cycles back and forth between a maximum water level and a water level of effectively zero, at which time mostly air flows through the outlet. When the water level above the outlet is decreasing and reaches a certain height of only a couple inches above the outlet, the sound of the water flowing through the outlet becomes noisy as the water whirlpools out through the outlet. As the water level above the outlet further decreases, the noise of the water flowing through the outlet increases. Finally, as the water level approaches effectively zero such that mostly air flows through the outlet, the sound of the air and water flowing through the outlet becomes extremely noisy. Subsequently, the water level above the outlet rises back to the maximum level, and this noisy cycle is repeated over and over. Unfortunately, some people find this cycle of noise to be annoying. As a result, this cyclical noise is an undesirable characteristic of prior art pre-filters.
Additionally, the larger box of the pre-filter which hangs on the wall of the aquarium is square shaped. Because the larger box hangs on the wall of the aquarium, the aquarium itself must sit enough away from a wall of the room in which it sits such that there is enough room between the wall of the room and the wall of the aquarium for the larger box to hang. Because the larger box is square, the space required to be left between the wall of the room and the wall of the aquarium is not minimized. Therefore, the aquarium takes up more space in the room in which it is located. Additionally, small children may crawl or walk behind the aquarium, and this can prove dangerous.
The difficulties discussed hereinabove are substantially eliminated by the present invention.